A 21-year-old man was referred to our tertiary care hospital with a congenital left hemifacial weakness and a chronic unilateral left-sided hearing loss that evolved since birth. On audiometry, normal hearing sensitivity in the right ear and a severe to profound sensorineural hearing loss with poor word recognition score in the left ear were noted. On physical examination, the patient presented a grade VI peripheral left facial paralysis. Findings from the rest of the clinical examination were within normal limits.
Results of cerebral magnetic resonance imaging (MRI) and temporal bone computed tomography (CT) revealed a left internal auditory canal mass, measuring 13×12 mm, developed at the expense of nerve VII, with a dilation of the various portions of the facial nerve with extension to its distal branches. It presented a hypointensity on T2, isointensity on T1, and was strongly enhanced after the injection of gadolinium. This mass was responsible for the enlargement of the internal auditory canal and was in close contact with the left middle cerebral fossa, without intraparenchymal extension (Figure 1A and B).